1. Field of the Invention
The invention is related to the field of roller bearings and concerns a roller element.
2. Description of Related Art
In the case of bearings, there is among others the problem that loads are to be moved with an as low an expenditure of force and with little friction. In doing so, the construction of conveying means is to be as simple as possible. For achieving of a linear, rotary or any other guided movement between bodies, wheels are utilised, which are attached to a first body and which roll on a second body. In case of high loads the number of wheels is increased. The problem of the minimization of friction, however, remains present and is now transferred to the bearing support of the wheels.
In the patent document GB 403 082 from the year 1932, an arrangement for the utilization in travelling trolleys and undercarriages is demonstrated, in the case of which several respectively axially connected pairs of rail wheels circulate around a pair of rails running in an oval shape. In doing so, the planes of the two rail ovals are parallel to one another. The axes of successive wheel pairs are coupled with one another through connection elements or connection springs or linked together. Each pair of wheels on the one hand runs on the mentioned rails with an oval shape, and on the other hand on a stationary pair of rails or on the edges of an I-beam. When driving around the end segments of the rail ovals, the ideal chain length varies depending on the position of the wheels. This is illustrated by FIG. 36: A first position of wheels 3 and linking plates 4 is indicated with continuous lines. If the wheel on the left on top is displaced to the right by a distance D, and if all wheels remain in contact with the rail oval, then a second position results, which is indicated by broken lines. In doing so, the lowest drawn wheel is displaced by a distance, which is smaller by d than D. In the patent document GB 403 082 the springs pull the chain of wheel pairs together and so effect an equalization of the length, in order to keep the wheels on the rails with an oval shape. The construction described in accordance with the field of application (cranes, railways) is designed for very high loads, which leads to the illustrated selection of rails and rail wheels.
Furthermore the patent document GB 387 403 demonstrates creeper chains for heavy vehicles such as mobile artillery guns. The creeper chains on individual sections of their continuous track are supported on rollers moving along with them. The rollers are coupled together through their axles and run around a central body. For the movement of the vehicle, the creeper chains are driven by a drive wheel.
The mentioned devices from vehicle engineering, because they are designed for different requirements, in particular for—viewed absolutely—high loads and greater dimensions, are not capable of being utilized in materials handling technology in an efficient manner.
In AT 387 156, a ski for grass surfaces with a circulating roller running carriage is disclosed. In one embodiment, the rollers are attached to a link belt, wherein on its links extensions are developed, which grip underneath a guide rail and as a result maintain the rollers in contact with the guide rail. It is to be anticipated that this arrangement is susceptible to wear.